Laboratory of Microbial Enzymology, G. K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, Russia.
Biodegradation. 2010 Jun;21(3):403-10. doi: 10.1007/s10532-009-9310-y. Epub 2009 Nov 10.
Biodegradation of glyphosate in sod-podzol soil by both the indigenous micro flora and the introduced strain Ochrobactrum anthropi GPK 3 was studied with respect to its sorption and mobility. The experiments were carried out in columns simulating the vertical soil profile. Soil samples studied were taken from soil horizons 0-10, 10-20, and 20-30 cm deep. It was found out that the most of the herbicide (up to 84%) was adsorbed by soil during the first 24 h; the rest (16%) remained in the soluble fraction. The adsorbed glyphosate was completely extractable by alkali. No irreversible binding of glyphosate was observed. By the end of the experiment (21st day), glyphosate was only found in extractable fractions. The comparison of the effect of the introduced O. anthropi GPK 3 and indigenous microbial community on the total toxicant content (both soluble and absorbed) in the upper 10 cm soil layer showed its reduction by 42% (21 mg/kg soil) and 10-12% (5 mg/kg soil), respectively. Simultaneously, 14-18% glyphosate moved to a lower 10-20 cm layer. Watering (that simulated rainfall) resulted in a 20% increase of its content at this depth; 6-8% of herbicide was further washed down to the 20-30 cm layer. The glyphosate mobility down the soil profile reduced its density in the upper layer, where it was available for biodegradation, and resulted in its concentration in lower horizons characterized by the absence (or low level) of biodegradative processes. It was shown for the first time how the herbicide biodegradation in soil can be increased manifold by introduction of the selected strain O. anthropi GPK 3.
在 sod-podzol 土壤中，通过土著微生物群落和引入的 Ochrobactrum anthropi GPK 3 菌株对草甘膦的生物降解进行了研究，重点研究了其吸附和迁移性。实验在模拟垂直土壤剖面的柱中进行。研究的土壤样本取自 0-10、10-20 和 20-30 cm 深的土壤层。结果发现，在最初的 24 小时内，大部分除草剂（高达 84%）被土壤吸附；其余的（16%）留在可溶部分。吸附的草甘膦可完全用碱提取。未观察到草甘膦的不可逆结合。到实验结束时（第 21 天），仅在可提取部分发现草甘膦。比较引入的 Ochrobactrum anthropi GPK 3 和土著微生物群落对上层 10 cm 土壤层中总毒性物质含量（可溶部分和吸收部分）的影响，发现其分别减少了 42%（21 mg/kg 土壤）和 10-12%（5 mg/kg 土壤）。同时，14-18%的草甘膦迁移到下一个 10-20 cm 层。浇水（模拟降雨）导致该深度的含量增加了 20%；6-8%的除草剂进一步向下冲刷到 20-30 cm 层。草甘膦在土壤剖面上的迁移降低了其在上层中的密度，使其可用于生物降解，并导致其在下层中的浓度降低，而下层的生物降解过程不存在（或水平较低）。这是首次表明如何通过引入选定的 Ochrobactrum anthropi GPK 3 菌株，使土壤中除草剂的生物降解率成倍数增加。
